1. Field of Invention
This invention relates generally to apparatus for introducing adjustable and discretionary stiffness to a support device employed for providing resilient response to road shocks encountered by light vehicles such as bicycles or motorcycles. The apparatus can be installed at the seat, wheel forks, or other locations of such vehicles.
2. Brief Description of the Prior Art
The prior art is replete with efforts to deal with the effects of road shocks encountered during normal use of light vehicles such as bicycles and motorcycles. A variety of devices have been applied to the seats, wheel forks, and other locations of such vehicles. Some representative examples of the prior art will be described herein. Examples that employ spring-like devices or adjustable seat orientation include: U.S. Pat. Nos. 5,226,624 to Kingsbery; 5,294,173 to Yu; 5,294,174 to Bigolin; and 5,236,169 to Johnsen, the inventor of the present invention. An example that employs hydraulic damping is U.S. Pat. No. 5,301,974 to Knapp. While these devices may be suitable for the particular purposes they address, they would not be as suitable for the purposes of the present invention as hereinafter described.
Kingsbery discloses means for mounting a bicycle seat to the upper end of a support post of a bicycle frame. To vary the orientation of the seat, means for forward and rearward tilting is provided. Kingsbery also provides a means for preventing unwanted movement of the support and the seat with respect to the seat post.
Yu discloses a saddle (i.e. seat) support consisting of a metal tubular body mounted to the bottom side of a bicycle saddle. Disclosed are details of the tubular body that provides both structural support for the saddle and resilient response to road shocks.
Bigolin discloses a safety saddle for bicycles. A relatively stiff frame element is attached to the bicycle or motorcycle below a framework element that defines the seat portion of the saddle and provides support for the saddle. Two coil springs situated between the frame element and framework element allow relative movement, while resiliently resisting forces that would bring these members together. A telescoping element covering each coil spring prevents possible injury to the user by way of contact with compressing springs.
Knapp discloses a system for a bicycle or similar vehicle that applies shock isolation at the location of the seat, handle bar, or other location. Shock absorption is provided from the frame to the seat through the use of a hydraulic assembly featuring variable damping. Internal springs are included for the purpose of adjusting the preloading of the hydraulic system.
An additional item of prior art is a patent owned by the inventor of the present invention (U.S. Pat. No. 5,236,169). Disclosed is an assembly of two concentric coil springs for resilient response to road shocks and a support member that passes through the assembly of springs. In one embodiment of this concept, the two concentric springs are wound with opposite helical sense; although preferred, this relationship is not essential.
None of the prior art devices discloses arbitrary and discretionary setting of stiffness and means for adjusting resilient response to road shocks in the manner proposed by the present invention. Kingsbery merely provides for adjustable orientation of the seat. Both Yu and Bigolin provide spring-like resilient support but without means to adjust stiffness. Knapp provides adjustment for the purpose of controlling hydraulic damping action rather than to control resilient response to road shocks. Adjustable springs are employed internally to the hydraulic cylinder to set the pre-loading of the cylinder.